I used to have grip pressure problems too, my ball was drilled for my hand but the thumb hole was far too big. Maybe have an experience bowler/another PSO to look at your grip if see you have a similar issue, but if it doesn't, people usually recommend using tape (the white texturised ones).
A few games is way too few to determine if it's a residual habit, I personally take weeks to get rid of those.
If your thumb hole is small enough that you wouldn't be able to release it when you grip it, the habit will go away eventually because the feeling is absolutely terrifying. That was probably the worst stage of my bowling life so far, but I got there eventually.
There are also other products that helps your grip, cremes and rosin bags (for increasing grip I recommend the meshy balls, they tend to be grittier) etc.
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